Abstract: In this study, investigation and determination of the prevalence of parasitic trematodes and assessment of risk factors of trematode infection in cattle, sheep and goats were conducted from December, 2010 to April, 2011 in Hashim Nur’s Ethiopian livestock and meat export (HELMEX) abattoir at Debre Zeit, Ethiopia. One thousand one hundred fifty two samples of ruminants consisting of bovine (153), ovine (493) and caprine (506) were analyzed for the present of one or more trematods. The overall prevalence of trematodes in the study was 21% (242/1152). The specific prevalence of trematodes was found to be 3.6% (41/153) in bovine, 9.6% (111/493) in ovine and 7.8% (90/506) in caprine. Statistically analysis showed that there was significant difference (p<0.05) on the prevalence of trematodes among species. The 241 trematods isolates were identified by their morphologies for species assignment. The identification result of trematodes proved highest prevalence of fasciola hepatica (6.4%). The lowest prevalence of trematode infection from species assignment of the study was known to be Dicrocoelium dendriticum (2.3%). The prevalence of fasciola gigantica, Paramphistomum and mixed infection with one or more species was proved to be 2.5, 5.8 and 4%, respectively. Statistical analysis of the result showed the presence of significance difference (p<0.05) on the prevalence of trematodes in ruminants examined in this research. The high level of trematode isolate found in these ruminant samples in the present study represent high rate of infection and public health risk to the consumer (Fasciola). This suggests the need to implement strict control and prevention methds through implementation of recommended method in order to guarantee the quality of these highly popular meat and meat products in Debre Zeit, Ethiopia.